Funny the 37's operated over the San Juan extention throughout there careers and on the tighest curves on the entire ng that were found in Monero Canyon posed no issues for the Grande and the operation of the 37's through this area. Even when traffic dwindled in the late 60's there were more active 37's than 36's. The 497 had a bad lead truck which stemmed back to it's derailment on Cumbres in the early 60's. It's has since been fixed by the crew at Chama along with getting the 492 pilot truck. It's a shame the whole class gets a bad rap from one loco which had a major mechanical issue. It's surprising the D&S didn't discover this issue during it's tenure there. Just an observation.
William
aka drgwk37